Further Information

Climate Change

Human activities result in emissions of 45 billion tons of greenhouse gases each year. The main greenhouse gases are carbon dioxide (CO2), methane (CH4) and nitrous oxide or laughing gas (N2O). The main source of greenhouse gas emissions is fossil fuel combustion for electricity & heat, transportation, and manufacturing. Other sources are agriculture, deforestation and industrial processes. CO2 emissions have grown strongly over time, especially since the 1970s. After a small dip in 2009 due to the economic downturn, global CO2 emissions from fuel combustion have continued to grow, reaching a record level of 31.6 billion tons in 2011.

As a result, the concentration in the atmosphere of CO2 is steadily increasing, by ~2 parts per million (ppm) per year, and has almost reached 390 ppm, an increase of over 40% since the start of the Industrial Revolution.

The higher CO2 concentration has contributed to an increase of the average global temperature by 0.7 °C so far. Higher temperatures lead to changes in weather patterns that occur more rapidly than most ecosystems can deal with, which may result in extinction of species and disruption of food production systems. Other impacts include sea level rise and extreme weather events such as droughts, storms and heavy, concentrated rainfall.

If growth of greenhouse gas emissions continues unabated, the average global temperature could increase by 6 °C by the end of the century, compared to an average of about 14.5 °C today. Average temperatures at the poles could rise by 12 °C or more. Therefore, emissions of greenhouse gases need to be reduced significantly and rapidly, to mitigate the impact of climate change.